Ion implanter optimizer scan waveform retention and recovery

Abstract

Methods and apparatus are provided for controlling dose uniformity in an ion implantation system. According to one embodiment of the invention, an initial scan waveform is adjusted to obtain a desired uniformity for use in a first implant process, and the adjusted scan waveform is stored. The stored scan waveform is recalled and used in a second implant process. According to a another embodiment of the invention, desired beam parameters are identified and, based on the desired beam parameters, a stored scan waveform is recalled for use in a uniformity adjustment process, and the uniformity adjustment process is performed. According to a further embodiment of the invention, an apparatus is provided that includes a beam profiler for measuring a current distribution of a scanned ion beam. The apparatus also includes a data acquisition and analysis unit for adjusting an initial scan waveform based on a desired current distribution and the measured current distribution for use in a first implant process, storing the adjusted scan waveform, recalling the stored scan waveform, and using the recalled scan waveform in a second implant process.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of provisional application Ser. No. 60 / 232,704 filed Sep. 15, 2000, which is hereby incorporated by reference.FIELD OF THE INVENTION[0002]This invention relates to systems and methods for ion implantation of semiconductor wafers or other workpieces and, more particularly, to methods and apparatus for optimizing the uniformity of a scanned ion beam.BACKGROUND OF THE INVENTION[0003]Ion implantation is a standard technique for introducing conductivity-altering impurities into semiconductor wafers. A desired impurity material is ionized in an ion source, the ions are accelerated to form an ion beam of prescribed energy, and the ion beam is directed at the surface of the wafer. The energetic ions in the beam penetrate into the bulk of the semiconductor material and are embedded into the crystalline lattice of the semiconductor material to form a region of desired conductivity.[0004]Ion implantation systems us...

AI Technical Summary

Problems solved by technology

In general, the initial linear scan waveform may not produce a desired uniformity across the semiconductor wafer, and a nonlinear scan waveform may be required.

The setup process is typically time consuming and reduces the throughput of the ion implanters.

In practice, even the automated optimization process can be time consuming and detract from ion implanter throughput.

Images